Motion preserving spinal implant for total disc replacement

ABSTRACT

A motion preserving spinal implant is presented for use in placement between intervertebral space for total replacement of a degenerated spinal disc The motion preserving spinal implant has a pair of end plates sandwiched around an inner core and an outer core, with the inner core being concentrically positioned within the outer core. The outer core encapsulates the inner core and provides adequate sealing of the inner core while maintaining flexibility and elasticity to advantageously support physiological movements. The inner core is constructed of an elastomeric material and acts as a solid diaphragm in order to resist and withstand localized compression and other forces. The end plates provide anchoring and fusion with adjoining vertebra and hold the inner and outer cores in place. The motion preserving spinal implant restores the normal height and natural function of the degenerated spinal disc and preserves the natural motion of the spine.

The current application claims a priority to the U.S. Provisional Patentapplication Ser. No. 62/828,584 filed on Apr. 3, 2019. The currentapplication also claims a priority to the U.S. Provisional Patentapplication Ser. No. 62/837,474 filed on Apr. 23, 2019.

FIELD OF THE INVENTION

The present invention relates generally to human body implants. Moreparticularly, the present invention relates to a motion preservingspinal implant for replacement of a spinal disc.

BACKGROUND OF THE INVENTION

Spinal implants are intended to treat degenerative disc disease (DDD) orother disc injuries. Spinal fusion treatment is a widely used treatmentto alleviate pain, but limits range of motion and mobility for apatient. Total disc replacement is another treatment for discdegenerative disease that aims to preserve motion and limitcomplications related to spinal fusion such as adjacent level wear anddisc degeneration. Total disc replacement is an effective solution fordegenerative disc disease and gaining interest due to increasingprevalence of neck pain, lower back pain, and pain in general. Thus,there is a need for functional improvement. For an example, withoutlimitations, there is a need for total disc replacement spinal implantsthat reduce wear due to metal to metal sliding and corrosive surfaces,increase cushioning, improve shock absorption, reduce wear debris ofmetal, and maintain spinal motion range.

The present invention solves these problems by providing a treatmentsolution that reduces degeneration due to metal wear because of nosliding between metal plates, increases cushioning with effective innercore design features, and uses special polymeric and elastomericmaterials having varying hardness and physical properties such assilicone or liquid silicon rubber that also provides shock absorption,and maintains range of motion due to effective outer core design, itsfeatures, and choice of materials. All components in the assembly aredesigned such that it can effectively resist compression forces,shear-compression forces, and torsion forces.

Additional advantages of the invention will be set forth in part in thedescription which follows, and in part will be obvious from thedescription, or may be learned by practice of the invention. Additionaladvantages of the invention may be realized and attained by means of theinstrumentalities and combinations particularly pointed out in thedetailed description of the invention section. Further benefits andadvantages of the embodiments of the invention will become apparent fromconsideration of the following detailed description given with referenceto the accompanying drawings, which specify and show preferredembodiments of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of the present invention.

FIG. 2 is an exploded perspective view of the present invention.

FIG. 3 is a front view of the present invention.

FIG. 4 is a rear view of the present invention.

FIG. 5 is a top view and a side sectional view of the present invention.

FIG. 6 is a top view and a front sectional view of one of the end platesof the present invention.

FIG. 7 is a top view, a side sectional view, and a side view of theinner core of the present invention.

FIG. 8 is a top view, a side sectional view, and a side view of theouter core of the present invention.

FIG. 9 is a top view and a side sectional view of an alternativeembodiment of the present invention incorporating anchoring protrusions.

FIG. 10 is a top view and a side sectional view of one of the end platesin the alternate embodiment.

FIG. 11 is a top view and a side sectional view of the outer core in thealternate embodiment.

DETAIL DESCRIPTIONS OF THE INVENTION

All illustrations of the drawings are for the purpose of describingselected versions of the present invention and are not intended to limitthe scope of the present invention. The present invention is to bedescribed in detail and is provided in a manner that establishes athorough understanding of the present invention. There may be aspects ofthe present invention that may be practiced or utilized without theimplementation of some features as they are described. It should beunderstood that some details have not been described in detail in orderto not unnecessarily obscure focus of the invention. References hereinto “the preferred embodiment”, “one embodiment”, “some embodiments”, or“alternative embodiments” should be considered to be illustratingaspects of the present invention that may potentially vary in someinstances, and should not be considered to be limiting to the scope ofthe present invention as a whole.

The present invention is a spinal implant intended for use in totalreplacement of a degenerated spinal disc. In general, referring to FIGS.1-5, the present invention comprises a first end plate 1, a second endplate 2, an inner core 3, and an outer core 4. In the preferredembodiment of the present invention, the first end plate 1, the secondend plate 2, the inner core 3, and the outer core 4 each have generallyradial geometry, though it may be noted that other geometries may beutilized as desired or useful. The inner core 3 and the outer core 4 aregenerally disc-shaped, being substantially wider than tall, having aradial axial cross section and a certain thickness, or axial height. Theinner core 3 is positioned concentrically within the outer core 4, andthe outer core 4 is connected between the first end plate 1 and thesecond end plate 2 through a plurality of interlocking members 5. Thus,the inner core 3 and the outer core 4 are sandwiched by the first endplate 1 and the second end plate 2. More specifically, the outer core 4comprises an inner cavity 40 that centrally and axially traversesthrough the outer core 4. The inner core 3 is positioned within theinner cavity 40 of the outer core 4, such that the inner core 3 issealed by the outer core 4, the first end plate 1 and the second endplate 2. In some embodiments, the internal lateral geometry of the innercavity 40 may be determined by the external lateral geometry of theouter core 4.

In the preferred embodiment, the inner core 3 is constructed of amedical or implant grade polymeric or elastomeric material which mayhave varying hardness and other physical properties in variousembodiments. In some embodiments, the inner core 3 is constructed of asilicone material. In some embodiments, the inner core 3 is constructedof a medical or implant grade silicone elastomer with a hardness rangingfrom 60 shore A to 90 shore A. In some embodiments, the inner core 3 maybe constructed of a liquid silicone rubber (LSR) material. Such materialis inert and widely used in medical breast implants. Silicone rubber hasthe ability to retain its initial shape and mechanical stress under highcompression, shear-compression, flexural, torsional, and tensilestresses and has excellent creep properties. In other embodiments, otherappropriate materials may be used to manufacture the inner core 3. Theinner core 3 serves as a solid “diaphragm” or cushion that resists andwithstands localized compression, shear-compression, torsion, and otherforces. In various embodiments, the diameter of the inner core 3 mayrange from approximately 0.125 inches to 2.25 inches, but it should beunderstood herein that various dimensions of the present invention mayvary without departing from the intended spirit and scope of the presentinvention.

In the preferred embodiment, the inner core 3 comprises a first coreconvexity 30 and a second core convexity 31, as shown in FIGS. 5 and 7.The first core convexity 30 and the second core convexity 31 arepositioned axially opposite each other along the inner core 3. The firstcore convexity 30 and the second core convexity 31 are essentiallybulges centrally positioned on the inner core 3 that contribute to theinner core's 3 capabilities to resist and withstand any forces the innercore 3 is subject to while installed in a human spine. The first coreconvexity 30 and the second core convexity 31 further correspond to andmate with inner concavities on the first end plate 1 and the second endplate 2, as will be discussed hereinafter. In various embodiments, aconvexity angle of the first core convexity 30 and the second coreconvexity 31 may range from 5 degrees to 60 degrees, and an outer radiusof the first core convexity 30 and the second core convexity 31 mayrange from 0.075 inches to 2 inches in various embodiments. In someembodiments, the inner core 3 further comprises a lateral wall with aconvex curvature, whose radius may range in various embodiments from0.063 inches to 2.250 inches, but it should be understood herein thatvarious dimensions of the present invention may vary without departingfrom the intended spirit and scope of the present invention.

The outer core 4 acts as a sealing ring for the inner core 3 andprovides the necessary motion to the spine once the present invention isimplanted in a human body. In the preferred embodiment, the outer core 4is constructed of a polymeric or elastomeric material with varyinghardness and other physical properties in various embodiments.

In some embodiments, the outer core 4 may be constructed of anultra-high molecular weight polyethylene (UHMWPE) material. In someembodiments, the outer core 4 may be constructed of a medical gradepolypropylene (PP) material, though the material of the outer core 4 mayvary in different embodiments as desired. In general, it is desired touse a material with superior abrasive and corrosive resistance, highstrength, light weight, and low coefficient of friction in the outercore 4. In various embodiments, the diameter of the outer core 4 mayrange from 0.175 inches to 2.375 inches, though as previously mentioned,any dimensions listed for the various components of the presentinvention should not be considered to be limiting and may vary indifferent embodiments.

In the preferred embodiment, the first end plate 1 and the second endplate 2 are each constructed of a polyether ether ketone (PEEK)material, though the material of the first end plate 1 and the secondend plate 2 may vary in different embodiments. PEEK is increasinglyemployed as a biomaterial for trauma treatments, orthopedic, and spinalimplants. It is inherently strong, inert, and biocompatible. Propertiesthat make PEEK a material of choice for the end plates include: modulussimilar to bone, reduced stress shielding, artifact-free imaging, and anosteoconductive surface for bone on-growth. Alternatively oradditionally, PEEK material can be used in combination with a titaniummaterial or with a titanium plasma spray on the external surfaces of theouter core 4. The first end plate 1 and the second end plate 2 may beexternally treated with a titanium material in order to promotestrength, abrasion resistance, and friction reduction.

In the preferred embodiment, as shown in FIGS. 1-6, the first end plate1 and the second end plate 2 each comprise a plate body 20, an innerside 21, an outer side 22, a plate convexity 23, and a concavity 24,wherein a thickness of the plate body 20 extends between the inner side21 and the outer side 22. In various embodiments, the diameter of theplate body 20 may range from 0.375 inches to 2.5 inches, while thethickness may range from 0.031 inches to 0.375 inches, but it should beunderstood herein that various dimensions of the present invention mayvary without departing from the intended spirit and scope of the presentinvention.

In the preferred embodiment, the plate body 20 of the first end plate 1and the plate body 20 of the second end plate 2 are oriented at aspecified tilt angle 6 to each other, as illustrated in FIG. 1. Thespecified tilt angle 6 defines a deviation of the plate bodies of thefirst end plate 1 and second end plate 2 from being oriented parallel toeach other. The specified tilt angle 6 may vary in differentembodiments, mainly to correspond with different spinal disc types toreplace. In various embodiments, the specified tilt angle 6 may rangefrom 0.5 degrees to 15 degrees. In some embodiments, the specified tiltangle 6 may be less than 0.5 degrees. In some embodiments, the specifiedtilt angle 6 may be 0 degrees, such that the first end plate 1 and thesecond end plate 2 are oriented parallel to each other. In someembodiments, the specified tilt angle 6 may exceed 15 degrees.

The plate convexity 23 is centrally positioned on the outer side 22 ofthe plate body 20 for each of the first end plate 1 and the second endplate 2, similarly, the concavity 24 is centrally positioned on theinner side 21 of the plate body 20 for each of the first end plate 1 andthe second end plate 2. In some embodiments, the thickness of the platebody 20 is constant, and the plate convexity 23 and the concavity 24 areformed through a deviation from the generally flat geometry of the platebody 20, such that the thickness of the end plates at the plateconvexity 23 and concavity 24 is equal to the thickness of the endplates at their perimeter. In other embodiments, the plate convexity 23and the concavity 24 of the first end plate 1 and the second end plate 2may be formed independently of each other. In some embodiments, a filletmay be formed between the plate body 20 and the plate convexity 23 witha radius of, for example, but not limited to, a range from 0.015 inchesto 0.5 inches. The fillet serves to reduce any polymeric stress due tovertical localized compression forces on the first and second end plates2. The first core convexity 30 is positioned within the concavity 24 ofthe first end plate 1, and the second core convexity 31 is positionedwithin the concavity 24 of the second end plate 2.

As previously mentioned, the outer core 4 is connected between the firstend plate 1 and the second end plate 2 through the plurality ofinterlocking members 5. In some embodiments, the inner core 3 is furtherconnected between the first end plate 1 and the second end plate 2 inthe same manner through the plurality of interlocking members 5, thoughthis is not considered a requirement. More particularly, the inner side21 of the first end plate 1 is connected to the outer core 4 through theplurality of interlocking members 5, and the inner side 21 of the secondend plate 2 is connected to the outer core 4 opposite the first endplate 1 axially along the inner core 3 through the plurality ofinterlocking members 5.

In some embodiments, the first end plate 1 and the second end plate 2each further comprise an attachment flange 25 and at least one fasteneraperture 26. The attachment flange 25 may be used to anchor the presentinvention to adjoining vertebrae through one or more implant screws. Theinclusion of the attachment flange 25 in various embodiments will dependon end product requirements. The attachment flange 25 is perpendicularlyand perimetrically connected to the plate body 20, and extends away fromthe inner side 21, past the outer side 22 for each of the first endplate 1 and the second end plate 2, wherein the attachment flange 25 isconnected along a flange arc segment of the perimeter of the plate body20. Preferably, the attachment flange 25 does not extend past the innerside 21, though this may vary in different embodiments. The at least onefastener aperture 26 traverses through the attachment flange 25 for eachof the first end plate 1 and the second end plate 2. Each of the atleast one fastener aperture 26 may be a counterbore hole, a countersinkhole, a through hole, or other types of holes suitable for receivingvarious fasteners in different embodiments.

Furthermore, in some embodiments, the attachment flange 25 comprises aninner groove 27. The inner groove 27 traverses into and radially throughthe attachment flange 25 along the flange arc segment adjacent to theouter side 22 of the plate body 20 and adjacent to a perimeter of theplate body 20 for each of the first end plate 1 and the second end plate2. The inner groove 27 serves to provide clearance to the edge ofadjoining vertebra where the total disc replacement is being performedto reduce any wear from vertebral edges.

In the preferred embodiment, referring to FIGS. 2 and 5-7, the outercore 4 comprises a first plurality of core interlocking members 50 and asecond plurality of core interlocking members 51 from the plurality ofinterlocking members 5, wherein the first plurality of core interlockingmembers 50 and the second plurality of core interlocking members 51 arepositioned axially opposite each other along the outer core 4. Further,the first end plate 1 and the second end plate 2 each further comprise aplurality of plate interlocking members 52 from the plurality ofinterlocking members 5. The plurality of plate interlocking members 52is positioned concentrically around the convexity on the inner side 21of the plate body 20 for each of the first end plate 1 and the secondend plate 2. The first plurality of core interlocking members 50 of theouter core 4 is engaged with the plurality of plate interlocking members52 of the first end plate 1, and the second plurality of coreinterlocking members 51 of the outer core 4 is engaged with theplurality of plate interlocking members 52 of the second end plate 2.

Furthermore, in some embodiments, the present invention furthercomprises a plurality of interlocking member receiving channels 7, asshown in FIGS. 2, 5, 6, and 8. Each of the plurality of interlockingmember receiving channels 7 is positioned concentrically with andadjacent to one of the plurality of interlocking members 5, and each ofthe plurality of interlocking members 5 is positioned within one of theplurality of interlocking member receiving channels 7. The plurality ofinterlocking members 5 and the plurality of interlocking memberreceiving channels 7 are configured to resist extrusion of the innercore 3 and outer core 4 when the inner core 3 and outer core 4 aresubject to external forces. The specific configuration and shape of theplurality of interlocking members 5 and the plurality of interlockingmember receiving channels 7 may vary in different embodiments. Forexample, in some embodiments, the plurality of interlocking members 5and the plurality of interlocking member receiving channels 7 have adovetail mating configuration as shown in FIGS. 2 and 5-8, wherein across section width of each of the plurality of interlocking members 5increases with distance away from the axial center of the outer core 4,and wherein each of the plurality of interlocking member receivingchannels 7 is shaped inversely to the plurality of interlocking members5 to accommodate them. In some embodiments, a cross section of each ofthe plurality of interlocking members 5 resembles a “tooth”, having anangled protrusion with a circular element at the end, wherein the crosssection of the interlocking member receiving channels 7 would havecorrespondingly negative geometry to receive the tooth. In either case,the distal geometry of the interlocking members 5 has a greater radialwidth than the remainder of the interlocking members 5, facilitatingsecurement of the interlocking members 5 within the interlocking memberreceiving channels 7. Alternatively, in some embodiments, theinterlocking members 5 and receiving channels 7 may not vary inthickness, as shown in FIG. 9.

More particularly, FIGS. 9-11 illustrate an alternative embodimentwherein each of the plurality of interlocking members 5 is oriented at aspecified anti-extrusion angle 53 in order to adequately resistextrusion of the inner core 3 and/or outer core 4 as previouslydescribed. In such an embodiment. More particularly, each of the firstplurality of core interlocking members 50, the second plurality of coreinterlocking members 51, and the plurality of plate interlocking members52 is oriented at the specified anti-extrusion angle 53. The specifiedanti-extrusion angle 53 may be defined in various ways, but herein thespecified anti-extrusion angle 53 is defined in relation to a centralaxis 15 of the present invention. The central axis 15 may be consideredto be an axis about which the radial features of the present invention,such as, but not limited to the inner core 3 and the outer core 4, andthe plate body 20 are positioned concentrically about. Separate centralaxes may be defined as appropriate for the inner core 3, outer core 4,and plate body 20 in order to account for any angular discrepancies dueto the specified tilt angle 6.

It may be understood herein that due to the specified tile angle 6, truecentral axes of the plate body 20, inner core 3, and/or outer core 4 maynot be positioned exactly coincidental with each other. However, that isconsidered to be the case herein for the sake of simplicity.

It is important to define herein that the specified anti-extrusion angle53 should be oriented radially outward from the central axis, such thatan imaginary line extending outward from any given member of the firstplurality of core interlocking members 50 or the second plurality ofcore interlocking members 51 does not intersect with the central axis.This is important because an inwardly-oriented anti-extrusion angle 53would not be effective or as effective and may not provide effectiveinterlock as an outwardly-oriented anti-extrusion angle.

As previously mentioned, the plurality of interlocking members 5 and theplurality of interlocking member receiving channels 7 function primarilyto secure the inner core 3 to the first end plate 1 and the second endplate 2, but also secondarily to resist extrusion of the outer core 4(and inner core 3, in applicable embodiments) when the present inventionis subjected to external forces, compressive forces in particular. Whenthe present invention is subjected to an axial compressive force, theinner core 3 and outer core 4 will tend to deform a certain amount incompression axially and in expansion laterally. Thus, is it a concernthat subject to such forces, portions of the inner core 3 and outer core4 will “extrude” out of their designated positions and potentiallybecome misaligned or damaged. The plurality of interlocking memberreceiving channels 7 may function to provide some space to accommodatesuch extrusion, and moreover the physical interlocking between theinterlocking members 5 and interlocking member receiving channels 7prevents the inner core 3 and outer core 4 from becoming dislodged fromtheir positions relative to the first end plate 1 and the second endplate 2. The quantity of both the plurality of interlocking members 5and the plurality of interlocking member receiving channels 7 may varyin different embodiments, from 1 to 9, for example, though any quantityof interlocking members 5 and interlocking member receiving channels 7may be included as desired in various embodiments.

As previously mentioned, in various embodiments, the first end plate 1and the second end plate 2 may be oriented at a specified tilt angle 6to each other in order to imitate the geometry of a spinal disc to bereplaced by the present invention. As such, the plate body 20 of thefirst end plate 1, the plate body 20 of the second end plate 2, theinner core 3 and the outer core 4 may be understood to extend in alongitudinal direction between a proximal end 8 and a distal end 9. Theproximal end 8 and the distal end 9 are positioned diametricallyopposite each other for each of the plate body 20, the inner core 3, andthe outer core 4. The proximal ends 8 are defined herein to be radiallyaligned with each other and the distal ends 9 are radially aligned witheach other for each of the plate bodies of the first end plate 1 and thesecond end plate 2, the inner core 3, and the outer core 4. Thus, insome embodiments, the specified tilt angle 6 is defined in a planecoincident with the proximal ends 8 and the distal ends 9. In someembodiments comprising the flange attachment, the flange attachment ispositioned at the proximal end 8 for each of the first end plate 1 andthe second end plate 2. In various embodiments, the orientation andalignment of the specified tilt angle 6 may vary however, and should notbe considered to be limited to the foregoing description.

Moreover, referring to FIGS. 7-8, in some embodiments, the specifiedtilt angle 6 may be realized through a diametrical difference inthickness of the inner core 3 and the outer core 4, so that the axialouter ends of the inner core 3 and outer core 4 are oriented at thespecified tilt angle 6 to each other, and thus the first end plate 1 andthe second end plate 2, being generally flat, are oriented at thespecified tilt angle 6 to each other as a result. As such, a proximalthickness 10 and a distal thickness 11 of both the inner core 3 and theouter core 4 may be defined, wherein the proximal thickness 10 of theouter core 4 is the thickness of the outer core 4 at the proximal end 8of the outer core 4, the distal thickness 11 of the outer core 4 is thethickness of the outer core 4 at the distal end 9 of the outer core 4,the proximal thickness 10 of the inner core 3 is the thickness of theinner core 3 at the proximal end 8 of the inner core 3, and the distalthickness 11 of the inner core 3 is the thickness of the inner core 3 atthe distal end 9 of the inner core 3.

Thus, in some embodiments, the proximal thickness 10 of the inner core 3is greater than the distal thickness 11 of the inner core 3, and theproximal thickness 10 of the outer core 4 is greater than the distalthickness 11 of the outer core 4. Thus, the specified tilt angle 6 maybe determined in some embodiments by the difference between the proximalthicknesses 10 and the distal thicknesses 11. In other embodiments, thespecified tilt angle 6 may be determined through other means; forexample, the thickness of the inner core 3 and outer core 4 may beconstant, while the thickness of the first end plate 1 and second endplate 2 may vary instead.

In some embodiments of the present invention, as shown in FIG. 9, as analternative to the attachment flange 25, the first end plate 1 and thesecond end plate 2 further comprise a plurality of anchoring protrusions12. The plurality of anchoring protrusions 12 serve as an alternativemeans of mounting the first end plate 1 and the second end plate 2 toadjacent vertebrae. The anchoring protrusions 12 are connected to theouter side 22 and are preferably oriented perpendicular to the platebody 20. The anchoring protrusions 12 are distributed around the outerside 22 in any desirable configuration, such as, but not limited to,four anchoring protrusions positioned in a concentric 90 degree patternaround the plate convexity 25. Furthermore, each of the anchoringprotrusions 12 may comprise a plurality of teeth 13 positioned at adistal end 14 of the anchoring protrusions 12.

The components of the present invention may be manufactured through anydesirable manufacturing process, such as, but not limited to, 3Dprinting, CNC machining, injection molding, compression bolding, orother manufacturing processes. The inner core 3 is preferably injectionmolded through an insert molding process where the first end plate 1 andthe second end plate 2 serve as inserts. Alternatively, the inner core 3can be produced independently through an injection molding, compressionmolding, or 3D printing process and is subsequently assembled with thefirst end plate 1 and the second end plate 2. The outer core 4 ispreferably either injection molded or compression molded using an insertmolding process where an assembly of the first end plate 1, second endplate 2, and inner core 3 serve as inserts. Alternatively, the outercore 4 can be produced independently through injection molding,compression molding, or 3D printing and subsequently assembled with thefirst end plate 1, second end plate 2, and inner core 3. Furthermore, inthe preferred embodiment, at every stage of assembly of the presentinvention, the external surfaces of the various components of thepresent invention are treated to increase surface bonding to achievesufficient covalent, cohesive and/or adhesive bonds.

Although the invention has been explained in relation to its preferredembodiment, it is to be understood that many other possiblemodifications and variations can be made without departing from thespirit and scope of the invention as hereinafter claimed.

What is claimed is:
 1. A motion preserving spinal implant for total discreplacement comprising: a first end plate; a second end plate; an innercore; an outer core; the first end plate, the second end plate, theinner core, and the outer core each having radial geometry; the firstend plate and the second end plate each comprising a plate body, aninner side, an outer side, a plate convexity, and a concavity, wherein athickness of the plate body extends between the inner side and the outerside; the inner core comprising a first core convexity and a second coreconvexity positioned axially opposite each other along the inner core;the inner core being constructed of an elastomeric material; the innercore being positioned concentrically within the outer core; the outercore being connected between the first end plate and the second endplate through a plurality of interlocking members; the plate body of thefirst end plate and the plate body of the second end plate beingoriented at a specified tilt angle to each other, wherein the specifiedtilt angle defines a deviation of the plate body of the first end plateand the plate body of the second end plate from being oriented parallelto each other; the plate convexity being centrally positioned on theouter side of the plate body for each of the first end plate and thesecond end plate; the concavity being centrally positioned on the innerside of the plate body for each of the first end plate and the secondend plate; the inner side of the first end plate being connected to theouter core through the plurality of interlocking members; the inner sideof the second end plate being connected to the outer core through theplurality of interlocking members opposite the first end plate axiallyalong the inner core; the first core convexity being positioned withinthe concavity of the first end plate; and the second core convexitybeing positioned within the concavity of the second end plate.
 2. Themotion preserving spinal implant for total disc replacement as claimedin claim 1, wherein the specified tilt angle is within a range of 0 to15 degrees.
 3. The motion preserving spinal implant for total discreplacement as claimed in claim 1, wherein the first end plate and thesecond end plate are constructed of a polyether ether ketone (PEEK)material.
 4. The motion preserving spinal implant for total discreplacement as claimed in claim 1, wherein the first end plate and thesecond end plate are externally treated with a titanium material.
 5. Themotion preserving spinal implant for total disc replacement as claimedin claim 1, wherein the inner core is constructed of a polymericmaterial.
 6. The motion preserving spinal implant for total discreplacement as claimed in claim 1, wherein the inner core is constructedof an elastomeric material.
 7. The motion preserving spinal implant fortotal disc replacement as claimed in claim 1, wherein the outer core isconstructed of a polymeric material.
 8. The motion preserving spinalimplant for total disc replacement as claimed in claim 1, wherein theouter core is constructed of an elastomeric material.
 9. The motionpreserving spinal implant for total disc replacement as claimed in claim1 comprising: the outer core comprising an inner cavity; the innercavity centrally and axially traversing through the outer core; and theinner core being positioned within the inner cavity of the outer core,wherein the inner core is sealed by the outer core, the first end plateand the second end plate.
 10. The motion preserving spinal implant fortotal disc replacement as claimed in claim 1 comprising: the first endplate and the second end plate each further comprising an attachmentflange and at least one fastener aperture; the attachment flange beingperpendicularly and perimetrically connected to the plate body andextending away from the inner side, past the outer side for each of thefirst end plate and the second end plate, wherein the attachment flangeis connected along a flange arc segment of the perimeter of the platebody; and the at least one fastener aperture traversing through theattachment flange for each of the first end plate and the second endplate.
 11. The motion preserving spinal implant for total discreplacement as claimed in claim 10 comprising: the attachment flangecomprising an inner groove; and the inner groove traversing radiallythrough the attachment flange along the flange arc segment adjacent tothe outer side and adjacent to a perimeter of the plate body for each ofthe first end plate and the second end plate.
 12. The motion preservingspinal implant for total disc replacement as claimed in claim 1comprising: the outer core comprising a first plurality of coreinterlocking members and a second plurality of core interlocking membersfrom the plurality of interlocking members, wherein the first pluralityof core interlocking members and the second plurality of coreinterlocking members are positioned axially opposite each other alongthe outer core; the first end plate and the second end plate eachfurther comprising a plurality of plate interlocking members from theplurality of interlocking members; the plurality of plate interlockingmembers being positioned concentrically around the convexity on theinner side of the plate body for each of the first end plate and thesecond end plate; the first plurality of core interlocking members ofthe outer core being engaged with the plurality of plate interlockingmembers of the first end plate; and the second plurality of coreinterlocking members of the outer core being engaged with the pluralityof plate interlocking members of the second end plate.
 13. The motionpreserving spinal implant for total disc replacement as claimed in claim1 comprising: a plurality of interlocking member receiving channels;each of the plurality of interlocking member receiving channels beingpositioned concentrically with and adjacent to one of the plurality ofinterlocking members; and each of the plurality of interlocking membersbeing positioned within one of the plurality of interlocking memberreceiving channels, wherein the plurality of interlocking members andthe plurality of interlocking member receiving channels are configuredto resist extrusion of the inner core and outer core when the inner coreand outer core are subject to external forces.
 14. The motion preservingspinal implant for total disc replacement as claimed in claim 1comprising: the plate body of the first end plate, the plate body of thesecond end plate, the inner core and the outer core each extendinglongitudinally between a proximal end and a distal end, wherein theproximal end and the distal end are positioned diametrically oppositeeach other for each of the plate body, the inner core, and the outercore, wherein the proximal ends are radially aligned with each other andthe distal ends are radially aligned with each other for each of theplate bodies of the first end plate and second end plate, the innercore, and the outer core, and wherein the specified tilt angle isdefined in a plane coincident with the proximal ends and the distalends.
 15. The motion preserving spinal implant for total discreplacement as claimed in claim 14 comprising: the first end plate andthe second end plate each further comprising a flange attachment; andthe flange attachment being positioned at the proximal end for each ofthe first end plate and the second end plate.
 16. The motion preservingspinal implant for total disc replacement as claimed in claim 14comprising: a proximal thickness of the inner core at the proximal endof the inner core being greater than a distal thickness of the innercore at the distal end of the inner core; and a proximal thickness ofthe outer core at the proximal end of the outer core being greater thana distal thickness of the outer core at the distal end of the outercore, wherein the specified tilt angle is determined by the differencebetween the proximal thicknesses and the distal thicknesses.